Fusible switch for electrical panelboard



21, 1957 H. I. STANBACK ETAL- 3,354,277

FUSIBLE SWITCH FOR ELECTRICAL PANELBOARD Filed Dec. 23. 1964 2 Sheets-Sheet 1 E5 I ll 216 71 3.9 a J8 41 4540 53 f ag 64 644/ NOV. 21, 1967 L TANBACK ET AL 3,354,277

FUSIBLE SWITCH FOR ELECTRICAL PANELBOARD Filed Dec. 23. 1964 movable contact blade formed in United States Patent 3,354,277 FUSIBLE SWITCH FOR ELECTRICAL PANELBOARD Harris I. Stanback and Harry W. Curtis, Lexington, Ky.,

assignors to Square D Company, Park Ridge, 11]., a

corporation of Michigan Filed Dec. 23, 1964, Ser. No. 420,570 6 Claims. (Cl. 200-114) This invention relates generally to fusible switches, and more particularly to a fusible switch for use in an electrical panelboard.

An object of the invention is to provide a fusible switch having a casing, a pair of separable contacts, an operating handle operable selectively to effect engagement and separation of the contacts respectively with and from each other, and a fuse holder removably insertable in the casing axially of a cartridge fuse held thereby, the operating handle for the contacts also being operable selectively to effect locking of the fuse holder in the casing and releasing of the fuse holder from the casing. Another object is to provide a fusible switch having a casing and a fuse clip in the casing for receiving a ferrule of a cartridge fuse axially of the fuse and engaging the ferrule on diametrically opposite side portions thereof.

A further object is to provide a fusible switch having a casing, a fuse clip in the casing, a terminal strap having a stationary contact portion in the casing, a fuse holder removably insertable in the casing axially of a cartridge fuse held thereby to engage one ferrule of the cartridge fuse with the fuse clip in the casing, the fuse holder including a combination fuse clip and movable contact a fuse clip portion of which engages the other ferrule of the cartridge fuse and a movable contact portion of which engages the stationary contact portion of the terminal strap, an indicating lamp disposed in the casing and having a pair of lead wires, and means for electrically connecting the lead wires of the indicating lamp respectively to the terminal strap and the fuse clip in the casing.

A still further object is to provide a fusible switch having a casing and a fuse holder removably insertable in the casing axially of a fuse held thereby, the fuse holder including an elongated body portion formed of insulating material and having a recess in a side thereof for receiving a shiftable interlock member and a recess in an inner end surface thereof, and a combination fuse clip and one piece and including a fuse clip portion received in the recess in the inner end surface of the body. portion and a movable contact blade portionfextending from the body portion adjacent an opposite side thereof from the recess for receiving the interlock member.

Other objects and advantages will appear when the following specification is considered along with the accompanying drawings in which:

FIG. 1 is a side view of a fusible switch constructed in accordance with the invention, the operating handle therefor being in ON position;

FIG. 2 is an end view of the switch of FIG. 1;

FIG. 3 is a top view of the switch of FIG. 1;

FIG. 4 is an enlarged sectional view of the switch of FIG. 1 taken generally along the line 4-4 of FIG. 7;

FIG. 5 is a perspective view of the fuse holder of the switch of FIG. 1;

FIG. 6 is a sectional view taken generally along the line 66 of FIG. 5;

FIG. 7 is an enlarged view similar to FIG. 1 but with the cover of the switch removed, the operating handle shifted to OFF position, and shown in section;

FIG. 8 is a fragmentary view similar to FIG. 7, but

portions of the fuse holder with the operating handle shown in section and shifted to ON position;

FIG. 9 is a perspective View of the spring anchoring member of the switch of FIG. 1;

FIG. 10 is a perspective view arm of the switch of FIG. 1;

FIG. 11 is an enlarged sectional view taken generally along the line 1111 of FIG. 7; and

FIG. 12 is a sectional view taken generally along the line 12-12 of FIG. 7.

With reference to the drawings, a fusible switch 12 constructed in accordance with the invention includes a casing 13 molded of insulating material and having a base portion 14 and a cover portion 16 provided with appro' priate recesses and projections for receiving and entrapping the various working parts of the switch, and secured together as by a plurality of rivets 18.

The switch 12 is provided adjacent one end of the easing 13 with a line terminal 20 which is shown, in the embodiment of the invention disclosed, as a terminal of the bolt-on type having a screw 22 for securing the terminal 20 to a bus bar (not shown) of an electrical panelboard. An inner end portion of the terminal 20 is provided with a stationary contact 24, as best shown in FIG. 7. A resilient mounting clip 26 is provided adjacent the other end of the casing 13.

An operating handle 28 molded of insulating material is mounted for pivotal movement to ON and OFF positions in the casing 13 by means of a pair of trunnions 29 formed integrally with the handle and received in circular recesses respectively in the base portion 14 and cover portion 16, as best shown in FIG. 4. Suitable ON and OFF indicia are provided on the base portion 14 for indicating the ON and OFF positions of the handle 28, as shown in FIG. 3.

A generally channel-shaped, elongated movable con tact arm 30 is arranged to pivot oppositely to the direction of selective pivotal movement of the operating handle 28, which is provided with a pair of spaced, depending leg portions 31 disposed generally inwardly of the trunnions 29. The contact arm 30, best shown in FIG. 10, is provided with a movable contact 32 secured to a bottom portion of the channel adjacent an inner end of the contact arm and engageable with the stationary contact 24 in the ON position of the handle, as shown in FIG. 8. The side portions of the channel-shaped contact of the movable contact arm 30 are elongated adjacent an outer end of the contact arm to provide a pair of spaced-apart leg portions 34 having rounded outer end portions pivotally received respectively in a pair of recesses 36 provided respectively in the depending leg portions 31 formed integrally with the handle 28. An arc shield 38 formed of electrically insulating material is hooked adjacent one end in a slot 30a (FIG. 10) in the contact arm 30, the other end portion of the arc shield 38 being slidably received in a recess 39 in the casing 13.

The contact arm 30 moves with a snap action provided by a tension spring 40hooked at one end in a slot 30b (FIG. 10) in the bottom portion of the channel-shaped contact arm and at the other end of an arm 42 of a spring anchoring member 43 secured in the base portion 14 and best shown in FIG. 9. The arm 42 is disposed between member 43 is held in place by the projection 45, which is received in a recess in the base portion 14.

Secured within the base portion 14 is a generally U- shaped fuse clip 48 the bight portion of which is circular and the leg portions of which are formed to partially define a hollow circular cylinder open at one end to receive an end ferrule of a cartridge fuse 50 axially of the fuse. One leg portion of the fuse clip 48 is provided with an extension 52 which aids in the securing of the fuse clip 48 in the base portion 14 and is electrically connected to the contact arm 30 through a flexible cable 54 having one end portion brazed or otherwise secured to the extension 52 and the other end portion brazed to the contact arm 30 and also held by a bent-over tongue portion 55 (FIG.

A combination load terminal and stationary contact member 56 is provided adjacent the opposite end of the casing 13 from the line terminal and above the mounting clip 26. The member 56 includes a terminal body portion 56a formed integrally with a terminal strap portion 56b and a stationary contact portion 560. A clamping screw 58 is threadedly mounted in the terminal body portion 56a.

A fuse holder 60 best shown in FIG. 5 is removably insertable in the casing 13 axially of the cartridge fuse 50 held thereby. The fuse holder 60 includes a body 62 formed of insulating material integrally with a handle 62a, and a combination fuse clip and movable contact blade member 64 including a fuse clip portion 64a and a movable contact blade portion 64b. The fuse clip portion 64a in which the fuse 50 is held is received in a recess in the inner end of the body 62 and the contact blade portion 64b extends outwardly therefrom for engagement with the stationary contact portion 560 of the member 56. As best shown in FIGS. 7 and 8, the member 64 includes a projection 64c having a resilient anchoring tongue 64d sheared outwardly therefrom for locking the member 64 in place in the body 62.

Interlock means are provided for preventing insertion and removal of the fuse holder 60 when the switch is in ON position. Thus, the body 62 is provided with a recess 62b for receiving an end portion 66a of a shiftable interlock member 66 as shown in FIGS. 4 and 8 when the handle 28 is shifted to ON position. The member 66 is retained in the base portion 14 and biased against the handle 28 by a compression spring 68. An end portion 66b of the member 66 opposite the end portion 66a is received in a groove 28a (FIG. 4) in the handle 28. The end portion 66b is rounded and the groove 28a is partially defined by a cam surface 28b, (FIGS. 7 and 8) which drives the end portion 66a into the recess 62b when the handle 28 is shifted to ON position. The recess 62b is partially defined by a surface 62c which is engageable with the end portion 66a to prevent removal of the fuse holder 60 from the casing 13 when the switch is in ON position. Insertion of the fuse holder 60 into the casing 13 sufficiently for the movable contact blade portion 64b to engage the stationary contact portion 56c is prevented when the handle 28 is in ON position by engagement of the inner end of the body 62 of the fuse holder with the end portion 66a.

An indicating lamp 70is provided in the base portion 14 and is visible through an aperture 71 provided therein. When the switch is energized and the handle 28 is in ON position, the lamp 70 glows if the fuse 50 either is blown, or is not present in the casing. The lamp is provided with a pair of lead wires 72a and 73 electrically connected respectively to the fuse clip 48 and the terminal strap portion 56b. A spring clip 75 is provided to hold the wire 73 in electrical engagement with the terminal strap portion 56b, as best shown in FIG. 11. The wire 72a is connected to a resistor 76 which in turn is connected to a wire 72b. The wire 72b is received in an aperture 48b (FIG 12) in a tongue portion 48a sheared and bent out from the fuse clip 48. A helical compression spring 78 disposed in the base portion 14 surrounds the tongue portion 48a and presses the wire 72b into electrical engagement with the fuse clip 48. t

It will be seen that an improved fusible switch for use in an electrical panelboard has been provided in which a fuse holder is removably insertable in the switch casing axially of a cartridge fuse held thereby and an operating handle for the switch also operates an interlock mechanism for the fuse holder to prevent removal of the fuse holder when the switch handle is in ON position.

It will also be seen that a novel fuse clip for a fusible switch has been provided, the fuse clip being formed in one piece and receiving a ferrule of a cartridge fuse axially of the fuse and engaging the ferrule on diametrically opposite side portions thereof. Further, improved means of electrically connecting the lead wries of an indicating lamp respectively to a fuse clip and a terminal strap of a fusible switch has been provided.

Various modifications may be made in the structure shown and described without departing from the spirit and scope of the invention.

We claim:

1. A fusible switch comprising a casing and a fuse clip secured in said casing, said fuse clip being generally U- shaped and including a generally fiat bight portion and a pair of spaced leg portions integral with and extending from said bight portion, and said fuse clip also having a shape such that said leg portions extend from said bight portion in a direction parallel to the longitudinal axis of a cartridge fuse when a ferrule of a cartridge fuse is mounted in said fuse clip, at least one of said leg portions being arcuately curved about an axis disposed between said leg portions and extending perpendicularly to said bight portion, and one of said leg portions having an extension thereon cooperating wi-th said casing to secure said fuse clip therein and serving as a terminal for the connection to said fuse clip.

2. A fusible switch comprising a casing, a stationary contact in said casing, an elongated movable contact arm in said casing, said contact arm having a pair of opposite end portions, a movable contact secured to one end portion of said contact arm and engageable with said stationary contact, contact arm mounting means in said casing on which the other end portion of said contact arm is mounted to accommodate rotational movement of said contact arm, an operating handle pivotably mounted in said casing and having an outer portion disposed outwardly of said casing and an inner portion disposed in said casing, said outer handle portion being alternatively movable in opposite directions respectively to ON and OFF positions relatively to said casing, said inner handle por tion having cam means thereon, a tension spring in said casing having one end portion connected to said contact arm between the opposite end portions thereof, said tension spring biasing said contact arm toward said operating handle, means operatively connecting said operating handle, tension spring, and contact arm in a manner such that movement of said outer handle portion respectively to said ON and OFF positions moves a line of action of said tension spring relatively to said contact arm mounting means to dispose said line of action respectively on opposite sides of said contact arm mounting means and effect movement of said movable contact respectively into and out of engagement with said stationary contact, a fuse holder separate from said operating handle and removably mounted in said casing in spaced relationship to said operating handle transversely of a pivotal axis thereof, means connecting a cartridge fuse electrically in series with said contacts when said fuse holder is mounted in said casing with a cartridge fuse mounted in the fuse holder, said fuse holder being alternatively removable from and insertable into said casing axially of a cartridge fuse when a cartridge fuse is mounted in said fuse holder, said fuse holder and easing having cooperative means preventing said fuse holder from being inserted into said casing in other than a particular position with respect thereto, a shiftable elongated interlock member reciprocably mounted in said casing between said operating handle and fuse holder for movement toward and away from said fuse holder, said fuse holder having a recess therein in which a first end portion of said interlock member is receivable, and means biasing said interlock member toward said operating handle, said cam means on said inner handle portion being engageable with a second end portion of said interlock member opposite said first end portion to shift said interlock member and move said first end portion into said recess in said fuse holder upon movement of said outer handle portion to said ON position.

3. A fusible switch as claimed in claim 2, wherein said cam means on said inner handle portion is disposed on an opposite side of the pivotal mounting of said operating handle from said outer handle portion.

4. A fusible switch as claimed in claim 2, wherein said contact arm mounting means is formed in said operating handle and is moved across said line of action of said tension spring upon movement of said outer handle portion from one to the other of said ON and OFF positions.

5. A fusible switch as claimed in claim 2, including a fuse clip secured in said casing and adapted to receive one ferrule of a cartridge fuse, said fuse clip remaining in said casing when said fuse holder is removed therefrom, a terminal strap having an inner end portion disposed in said casing, and a blown fuse indicating lamp in said casing on the other side of said fuse holder from said operating handle, said lamp having a pair of lead wires electrically connected respectively to said terminal, said fuse holder includes a combination fuse clip and movable contact blade member a fuse clip portion of which is adapted to receive another ferrule of a cartridge fuse and a movable contact blade portion of which engages said inner end portion of said terminal strap when said fuse holder is mounted in said casing.

6. A fusible switch comprising a casing, a fuse clip secured in said casing, said fuse clip being generally U- shaped and including a bight portion and a pair of spaced leg portions extending from said bight portion, said fuse clip also having shape such that said leg portions extend from said bight portion in a direction parallel to the longitudinal axis of a cartridge fuse when a ferrule of a cartridge fuse is mounted in said fuse clip, a blown fuse indicating lamp disposed in said casing and having a pair of lead wires extending therefrom, and means securing one of said lead wires to said fuse clip, said means including a tongue sheared and bent out from said fuse clip and having an aperture through which said one lead wire extends, and a helical compression spring mounted on said tongue and maintaining said one lead wire in electrically connected relationship with said fuse clip.

References Cited UNITED STATES PATENTS 1,556,825 10/ 1925 Wyman 2003 2,811,607 1 0/1957 Dorfman et al. 200116 3,009,036 11/1961 Dorfman et al. 200-414 3,213,249 10/ 1965 Ellsworth et al. 200116 3,240,903 3/ 1966 Groves et al. 200-121 1,812,307 6/ 1931 Schneider 339254 1,966,716 7/ 1934 Green 2001 14 2,417,692 3/1947 Kline 200'129 X 2,831,087 5/1958 Sundt 200-129 FOREIGN PATENTS 562.931 12/ 1957 Belgium.

BERNARD A. GILHEANY, Primary Examiner. H. E. SPRINGBORN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,354,277 November 21, 1967 Harris I. Stanback et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 60, for "of", first occurrence, read to column 5, line 31, after "terminal" insert strap and said fuse clip, and wherein Signed and sealed this 3rd day of December 1968.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

1. A FUSIBLE SWITCH COMPRISING A CASING AND A FUSE CLIP SECURED IN SAID CASING, SAID FUSE CLIP BEING GENERALLY USHAPED AND INCLUDING A GENERALLY FLAT BIGHT PORTION AND A PAIR OF SPACED LEG PORTIONS INTEGRAL WITH AND EXTENDING FROM SAID BIGHT PORTION, AND SAID FUSE CLIP ALSO HAVING A SHAPE SUCH THAT SAID LEG PORTIONS EXTEND FROM SAID BIGHT PORTION IN A DIRECTION PARALLEL TO THE LONGITUDINAL AXIS OF A CARTRIDGE FUSE WHEN A FERRULE OF A CARTRIDGE FUSE IS MOUNTED IN SAID FUSE CLIP, AT LEAST ONE OF SAID LEG PORTIONS 